The acronym SaaS stands for Software as a Service in software delivery models. SaaS is a cloud-based service model that allows users to access applications via the internet, eliminating the need for local installation. This model enables subscription-based pricing, where customers pay for usage rather than owning the software outright. SaaS offers scalability, automatic updates, and management, providing businesses with flexibility and reduced IT overhead. Common examples include applications for email, collaboration, and customer relationship management, making SaaS an appealing choice for many organizations.